ual to that of reciting to a judicious teacher before a large class of
fellow-students. By a proper and skilful use of the art of questioning,
under the excitement of answering before a large class, the mnemonic
power is subjected to a healthy and invigorating test, and all such
exercises promote powerfully the mental growth. A child may absorb
knowledge by mere solitary reading and study, just as a sponge absorbs
water, but the knowledge so acquired readily evaporates, or is squeezed
out. Something is needed to fix in the mind the knowledge that has been
lodged there, and no process is more effectual to this end than that of
class recitation. It is by telling other people what we have learned,
that we learn it more effectually, and make it more completely our own.
A good teacher, by good methods of recitation, can do more than all
other persons and all other things to secure a sound and healthy growth
of memory in the young.

Another thing highly necessary in cultivating a really good memory, is
attaining the utmost possible clearness in our ideas. If the knowledge,
when it first comes into the mind, is clearly and sharply defined, so
that we really know a thing, instead of having vague and confused
notions about it, we shall be the more likely to remember it
permanently. Nothing is more conducive towards giving these sharp and
definite impressions than the use of visible illustrations. Actual
exhibition before a class of the objects talked about, actual
experiments of the operations described, and the constant use of the
chalk and the blackboard, presenting even abstract truths in concrete
and visible symbols, as is done in algebra, chemistry, and logic, are
among the means by which, chiefly, knowledge becomes well defined to the
mind. Such is the constitution of the mind, that we have a clearer
apprehension of what we see than of what comes to us through any other
sense, and the knowledge which comes to us by means of the sight, is, of
all kinds of knowledge, the most lasting and the most easily recalled.
Hence, in teaching, it is hardly possible to exaggerate the importance
of visible illustration.

Another condition extremely favorable to the growth of memory, is the
existence of a considerable degree of mental excitement at the time that
knowledge enters the mind. Metals weld easily only at a white heat. If
we would obtain a vigorous grasp of knowledge, and incorporate it
thoroughly into our other mental products